To a great extent, positive health behaviors are self-regulatory processes determined and limited by beliefs, attitudes, and knowledge; physical and social environments; and skill or performance behaviors. These factors comprise the main components of two major theories for the explanation of behavior and behavior change: Fishbein and Ajzen's theory of reasoned action and Bandura's social learning theory. The purpose of this investigation is to test the relative effectiveness of social learning theory and the theory of reasoned action for understanding and predicting oral health behavior and to test the effectiveness of a cognitive-behavioral intervention strategy for enhancing long-term adherence to a homecare regimen. Based on social learning theory the intervention utilizes performance exposure and participant modeling induction for experiencing performance accomplishments. Study participants will view oral pathogens through phase contrast microscopy, receive corrective feedback, perform self-ratings, and perform ratings of a live model with optimal oral hygiene. A pre-test, multiple post-test randomized control group design will be used. A total of 249 adult subjects will receive oral prophylaxis and instruction (control) or prophylaxis, instruction, and cognitive-behavioral enhancement involving either performance exposure (phase contrast microscopy, corrective feedback, self-rating) or performance exposure plus participant modeling (phase contrast microscopy, corrective feedback, self-rating, ratings of a live model with optimal oral hygiene). All subjects will be repeatedly assessed for oral health status, variables pertinent to theory of reasoned action, and variables relevant to social learning theory explanations of behavior. This investigation will provide a better understanding of the cognitive, behavioral, and environmental variables related to long-term adherence to a positive oral health regimen. This research is also a required precursor for the design of clinically relevant behavior changes techniques.